NAME

stat - file status

LIBRARY

Standard C library (libc)

SYNOPSIS

#include <sys/stat.h>

struct stat {
    dev_t      st_dev;      /* ID of device containing file */
    ino_t      st_ino;      /* Inode number */
    mode_t     st_mode;     /* File type and mode */
    nlink_t    st_nlink;    /* Number of hard links */
    uid_t      st_uid;      /* User ID of owner */
    gid_t      st_gid;      /* Group ID of owner */
    dev_t      st_rdev;     /* Device ID (if special file) */
    off_t      st_size;     /* Total size, in bytes */
    blksize_t  st_blksize;  /* Block size for filesystem I/O */
    blkcnt_t   st_blocks;   /* Number of 512 B blocks allocated */

    /* Since POSIX.1-2008, this structure supports nanosecond

       precision for the following timestamp fields.

       For the details before POSIX.1-2008, see HISTORY.  */
    struct timespec  st_atim;  /* Time of last access */
    struct timespec  st_mtim;  /* Time of last modification */
    struct timespec  st_ctim;  /* Time of last status change */
#define st_atime  st_atim.tv_sec  /* Backward compatibility */
#define st_mtime  st_mtim.tv_sec
#define st_ctime  st_ctim.tv_sec
};

.st_atim, .st_mtim, .st_ctim:

    Since glibc 2.12:

        _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700

    glibc 2.19 and earlier:

        _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

Describes information about a file.

The fields are as follows:

.st_dev

This field describes the device on which this file resides. (The major(3) and minor(3) macros may be useful to decompose the device ID in this field.)

.st_ino

This field contains the file's inode number in the filesystem on .st_dev. If stat(2) was called on the mount point, then .st_ino differs from .d_ino returned by readdir(3) for the corresponding directory entry in the parent directory. In this case, .st_ino is the inode number of the root directory of the mounted filesystem, while .d_ino is the inode number of the mount point in the parent filesystem.

.st_mode

This field contains the file type and mode. See inode(7) for further information.

.st_nlink

This field contains the number of hard links to the file.

.st_uid

This field contains the user ID of the owner of the file.

.st_gid

This field contains the ID of the group owner of the file.

.st_rdev

This field describes the device that this file (inode) represents.

.st_size

This field gives the size of the file (if it is a regular file or a symbolic link) in bytes. The size of a symbolic link is the length of the pathname it contains, without a terminating null byte.

.st_blksize

This field gives the "preferred" block size for efficient filesystem I/O.

.st_blocks

This field indicates the number of blocks allocated to the file, in 512-byte units. (This may be smaller than .st_size/512 when the file has holes.)

.st_atime

This is the time of the last access of file data.

.st_mtime

This is the time of last modification of file data.

.st_ctime

This is the file's last status change timestamp (time of last change to the inode).

For further information on the above fields, see inode(7).

STANDARDS

POSIX.1-2024.

HISTORY

stat

POSIX.1-1988.

.st_rdev

.st_blksize

.st_blocks

SUSv1, POSIX.1-2001 XSI.

Initially, SUSv1 specified .st_blksize and .st_blocks with type long. This was remedied in SUSv2.

Old kernels and old standards did not support nanosecond timestamp fields. Instead, there were three timestamp fields —.st_atime, .st_mtime, and .st_ctime— typed as time_t that recorded timestamps with one-second precision.

Since Linux 2.5.48, the stat structure supports nanosecond resolution for the three file timestamp fields. The nanosecond components of each timestamp are available via names of the form .st_atim.tv_nsec, if suitable test macros are defined. Nanosecond timestamps were standardized in POSIX.1-2008, and, starting with glibc 2.12, glibc exposes the nanosecond component names if _POSIX_C_SOURCE is defined with the value 200809L or greater, or _XOPEN_SOURCE is defined with the value 700 or greater. Up to and including glibc 2.19, the definitions of the nanoseconds components are also defined if _BSD_SOURCE or _SVID_SOURCE is defined. If none of the aforementioned macros are defined, then the nanosecond values are exposed with names of the form .st_atimensec.

NOTES

The following header also provides this type: <ftw.h>.

SEE ALSO

stat(2), inode(7)